Members of Rapid Action Battalion (RAB) arrested another accused from Fenchuganj upazila early Monday in a case filed over Friday's gang-rape at MC College.
With the latest arrest, the number of arrestees in the case rose to five, police said.
The RAB team arrested the accused, Rajon, after conducting a raid on his relative's house in Kochua Noyatila area of the upazila around 1am, according to a source at Rab-9.
They also arrested his associate, Ainul, for assisting him to go into hiding.
Earlier, a team of detective branch of police arrested another accused Robiul Islam from Nabiganj upazila around 10pm on Sunday, said Anwar Hossain, additional superintendent of Habiganj police.
Meanwhile, another Rab team arrested accused Shah Mahbubur Rahman Roni from Habiganj sadar around 9pm, said ASP Obain, media officer of Rab-9.
Main suspect Saifur Rahman, son of Tauhid of Balaganj upazila, and Arjun Lashkar, was arrested from Noarai Ghat in Chhatak upazila of Sunamganj, said Mizanur Rahman, officer-in-charge of Chhatak Police Station.
Arjun, listed as the number 4 accused, was arrested from Mantala bordering area in Madhabpur upazila of Habiganj, said Madhabpur police OC Golam Dastagir.
A 19-year-old married girl was raped by a group of youths at the college dormitory on Friday night.
The suspects tied up the victim's husband and raped her in a hostel room of the college.
On information, police rescued the couple.
The victim's husband filed a case at Shah Poran Police Station in the early hours of Saturday against nine people mentioning the names of six.